"I was freaking out. I was like, 'He has no idea there's a shark right next to them," said photographer Matt Larmand.
"Immediately there was blood everywhere, the first bite punctured an artery," James White said.
The seal attack on Saturday marked the fourth time a shark has been spotted at Nauset Beach, leading to the closure.
The shark bit a large chunk out of the surfer's board as he hit the waves during sunset, forcing him to swim to shore to safety.
About a half-a-dozen sharks were captured enjoying a feeding frenzy in North Carolina waters.
The latest incident follows a series of shark attacks in the Sunshine State over the past few days.
New Smyrna Beach on the state's central east coast is considered to be the shark attack capital of the world, according to the International Shark Attack File.
While not a perfect experiment, the former NASA engineer came to a conclusion.
"We saw some more splashing of water, and then the blood started spreading out more," said a witness.
Police are investigating the legs, but aren't yet sure if any laws have been broken.
Jordan Lindsey, 21, died last month after being attacked by three sharks while swimming in waters off Rose Island. Now, her family says the tour guides lacked basic medical supplies.
Jordan Lindsey, 21, of Torrance, was swimming close to Rose Island when multiple sharks swam into the area. The victim suffered bites to her legs, buttocks, and her right arm was severed, police said.
Just a hungry shark in search of a snack.
The child—whose identity has not been released—was attacked while swimming in the ocean at around 4 p.m. south of Bald Head Island, a village official said.
Vidant Medical Center—with permission from the teenager's family—named the victim as Paige Winter, a 17-year-old girl. "She is in good condition," officials said.
"It all happened quickly, but I turned and saw that it had one of my legs in its mouth."
Glenn Dickson said the image of the shark tearing off his leg and swimming through his blood will never leave him.
"The injuries today are again a shark attack maul bite to the patient's thigh area with significant blood loss," one official said.
"It doesn't feel like I did anything heroic," the survivor said. "A lot of this was luck."
Some of the man's remains washed up near a tourist resort in Egypt.
"It was a ten-inch orangey body and then there was a fin and then I got out, and my leg was bloody," Lola Pollina, 12, said.
Melissa Brunning said it was not the shark's fault.
The shark was said to be four meters long.